As the amount of video content transmitted over networks increases, there is a growing need to monitor the quality of video content that is provided to end users. This is paramount in packet-based networks, such as the Internet, in which packets may not be delivered in a timely fashion or may be lost during delivery. By losing packets, the video provided to the end users may appear erratic or frozen for periods of time. To alert a video content provider to these periods of poor quality, the video content is monitored. Subjective, objective, or a combination of subjective and objective measurement techniques may be implemented for monitoring the video content. In general, subjective measurement techniques include human input and opinions whereas objective measurements are based on algorithms and methodologies that provide accurate and repeatable results. Since subjective measurements include one or more persons judging video quality, typically these techniques are considered impractical for measuring and assuring video quality in high volume situations. Consequently, the need for objective measurement algorithms and methodologies that are absent human intervention are in ever-increasing demand.
As mentioned above, as a sequence of video packets is sent from a source to one or more destinations, inevitably some of the packets are lost in route. To detect this packet loss, as each packet arrives at a destination, the packet may be accessed to retrieve a sequence number stored in the packet. This sequence number identifies the position that the packet is located in the sequence. By arranging the received packets based on these sequence numbers, the packet sequence may be reconstructed for presenting the video content to an end user.
In addition to losing video content, by losing individual video packets, one received video packet may be affected by the loss of another video packet. For example, video content stored in one video packet may be dependent upon video content stored in another video packet. Due to this inter-packet relationship, the video content of a received video packet may not be properly decoded if the received packet depends upon a lost video packet. Thus, even though a video packet has been received and designated as valid, by losing another video packet included in the same packet sequence, the video content stored in the received packet may be non-presentable to end users.